a. Field of the Invention
The instant invention relates to a system and method for multiple shell construction to emulate chamber contraction with a mapping system.
b. Background Art
Electrophysiology (EP) catheters have been used for an ever-growing number of procedures. For example, catheters have been used for diagnostic, therapeutic, mapping and ablative procedures, to name just a few examples. Typically, a catheter is manipulated through the patient's vasculature and to the intended site, for example, a site within the patient's heart, and carries one or more electrodes, which may be used for mapping, ablation, diagnosis, or other treatments.
In this regard, it is known to provide a catheter navigation and mapping system, as set forth in U.S. Pat. No. 7,263,397 issued to Hauck et al. entitled METHOD AND APPARATUS FOR CATHETER NAVIGATION AND LOCATION AND MAPPING IN THE HEART, assigned to the common assignee of the present invention, and hereby incorporated by reference in its entirety. Hauck et al. generally disclose a medical system for finding and displaying the location of electrodes within the body. Hauck et al. further disclose that a roving electrode is swept around in the heart chamber while the heart is beating, and a large number of electrode locations (“data points”) are collected. Such data points are taken at all stages of the heart beat and without regard to the cardiac phase. Since the heart changes shape during contraction only a small number of the points represent the maximum heart volume. Moreover, Hauck et al. teach selecting the most exterior points to create a “shell” representing the shape (geometry and/or volume) of the heart (or chamber thereof) at its maximum size. Once the shell is constructed, collected EP data may be subsequently mapped onto the shell and displayed to a user.
Thus, conventional high density mapping approaches create one static shell that the electrophysiologist may use, among other things, as a reference throughout a procedure such as an ablation procedure. The conventional practice of generating and using a single, static shell is not considered unreasonable inasmuch as in constructing just one shell using only the outermost points of the cloud, the electrophysiologist can be reasonably certain that these points coincide with the endo-cardial wall and not, for example, in a blood pool. However, it would nevertheless be desirable to provide a more realistic representation of the changing volume of a heart chamber as it changes throughout the different phases of the heart beat. For example, a more realistic representation would provide more useful information to the electrophysiologist regarding anatomic markers and whether, during ablation, intended targets have been successfully isolated.
Accordingly, there is therefore a need to minimize or eliminate one or more of the shortcomings set forth above pertaining to single shell construction and use.